Not applicable.
Not applicable.
1. Field of the Invention
The present invention generally relates to the cooling of heat-generating components in electronic apparatus and more particularly to the cooling of a heat-generating computer components. Still more particularly, the present invention relates to a spring-loaded heat dissipation apparatus that is particularly suited for use with heat generating components inside a computer.
2. Background of the Invention
As computer operating speeds and chip capacities keep increasing, it is becoming increasingly difficult to provide adequate cooling for processors and other high heat generating components used in electronic equipment. This is particularly true in the case of computers utilizing multiple processors and hot plug drive arrays. At the same time, as component density and power usage increase, it becomes increasingly important to remove the heat generated during operation so as to avoid overheating and ensure consistent operation of the devices.
For example, one trend in the computer industry has been to increase the number of CPUs per rack unit. Because rack space inside a computer is limited, there has been a trend toward packing more components, such as CPUs, memory, disk drives, and I/O, more and more closely together. As the components, each of which generate heat, are packed more closely together, air cooling becomes less feasible. Forced air cooling, which entails blowing air across hot components, or across a heat sink in thermal contact with the hot components, is limited to applications in which the flowing air can maintain a sufficient velocity across the hot components and thus can effectively remove heat from it. When components are packed together, it is no longer possible to achieve sufficient air velocity across the hot components.
This is particularly true when chips are disposed within multi-chip modules that generate significant amounts of heat. In addition, because there is a great demand to run these processor modules at higher speeds, the corresponding clock frequencies at which these devices must operate become higher. In this regard, it should be noted that power generation rises in proportion to the clock frequency. Accordingly, that the desire for faster computers generates not only demand for faster components, but also generates thermal demands in terms of energy that must be removed for faster, safer and more reliable circuit operation.
Until recently, extruded aluminum heat sinks have been considered sufficient for computer cooling needs. These metal heat sinks depend on air moving through the system to carry away waste heat, However, aluminum heat sinks have a number of well known disadvantages, which include the following: 1) heat sinks often obstruct access and impede processor removal; 2) the to include large heat sinks can force too wide spacing of multiple processors, causing signal propagation delay and package volume concerns; 3) the chassis design must allow sufficient air flow past the heat sink; 4) large heat sinks often obstruct air flow to other components; 5) large heat sink volumes decrease the density of a system design; 6) air heated by the processor heat sink is less effective for cooling other components in the electronic apparatus; 7) supporting the mass of a large heat sink poses mounting and vibration concerns; and 8) fans may be required to provide sufficient air flow across a heat sink.
With air cooling becoming less adequate, liquid cooling has begun to be more widely practiced for cooling computer components. In liquid cooling, sometimes also referred to as xe2x80x9ccold platexe2x80x9d cooling, a liquid is pumped through a closed loop cooling system and removes heat from heat exchangers that are in thermal contact with each of the processor chips (or other high heat-generating components or assemblies). Provided sufficient heat transfer occurs between the hot components and the liquid coolant, liquid cooling is much more effective than air cooling. On the other hand, liquid cooling requires a suitable heat transfer mechanism between the hot components and the coolant, and requires plumbing to handle the liquid cooling medium in both cooled and heated states. In instances where it is desired to provide hot-add and/or hot-replace access to the components, conventional cold plate installations often require disconnection of the fluid lines from the cold plates so as to allow access to the desired component(s).
Known techniques for achieving the required degree of thermal contact between a hot component and its associated cold plate typically involve cams or screws, which can maintain a desired amount of pressure at the interface between the hot component and the cold plate. However, cams may require special linkages to force the surfaces together during installation and to release contact prior to removal. Similarly, screws and/or bolts may be difficult to access and to or remove, particularly when the hot component is buried deep within the chassis or obstructed by other devices.
An example of such a linkage structure can be found in U.S. Pat. No. 5,886,872. The linkage structure allows the heat absorbing member to shift between first and second positions in which the heat absorbing member is alternately connected and disconnected from thermal contact with the heat generating electronic component. While such a linkage structure has clear advantages in ease of use, it is still desirable to provide a means by which a heat absorbing member can be effectively and quickly attached to a heat generating component.
In view of the foregoing problems, limitations and disadvantages associated with the above-mentioned cooling systems, it can seen that a need exists for an alternative type of cooling system that eliminates or at least substantially reduces such problems, limitations and disadvantages. In particular, it is desirable to provide a mechanism for applying a desired amount of pressure at the interface between the hot component and the cold plate. It is further desirable to provide a cooling device that is easy to install, and to eliminate the need for tools and/or special linkages for achieving thermal contact.
The present invention includes a cooling system that substantially reduces the problems, limitations and disadvantages described above. In particular, the present invention provides a mechanism for applying a desired amount of pressure at the interface between the hot component and the cold plate. The present invention further provides a cooling device that is easy to install and makes it possible to achieve and maintain the desired thermal contact without tools and/or special linkages.
In one preferred embodiment of the present invention, an electronic device such as a computer comprises a housing and a heat generating electronic component, such as a processor, disposed in the housing. To dissipate operating heat from the heat generating component, a heat dissipation apparatus is provided within the housing and comprises at least one heat absorbing member, a bracing member, and a holding structure connecting the heat absorbing member to the bracing member and supporting the heat absorbing member in a heat transfer relationship with the heat generating electronic component.
According to a feature of the invention, the holding structure is manually operable, without tools, to releasably clamp the heat absorbing member against the heat generating electronic component.
According to another feature of the invention, the heat generating electric component has at least one heat transfer surface that is provided with a tapered heat sink interposer. In one preferred embodiment, the heat generating electric component has two opposing heat transfer surfaces, each of which is provided with a tapered heat sink interposer. The heat absorbing member is provided with a corresponding pair of opposed heat absorbers supported on a spring-loaded holding device. The combination of the two tapered interposers forms a wedge-shaped body that easily slides between the two opposed heat absorbers, wedging them apart against the closing force applied by the spring-loaded holding device. In another embodiment, the heat generating electric component has only one heat transfer surface and the heat absorbing member is provided with one heat absorber, which contacts the heat transfer surface, and one bracing member, which contacts the opposite surface of the heat generating electric component.
According to another feature of the invention, at least one, and preferably both, of the heat absorbers comprises a liquid cooled cold plate. If both heat absorbers are not cold plates, the second heat absorbing member may comprise a finned metal heat sink member adapted for air cooling or some other suitable heat absorbing device.
The incorporation of the present heat dissipating apparatus in a computer allows sufficient cooling to be applied to even crowded, high-output systems and allows tool-less installation and removal access to the processor and near by equipment. The present system allows the disconnection of the heat absorbing member from thermal contact without necessitating disconnection of fluid flow lines.